Employers may select one of four options for determining the 12month period:
the calendar year;
any fixed 12month "leave year" such as a fiscal year, a year required by state law, or a year starting on the employee's "anniversary" date;
the 12month period measured forward from the date any employee's first FMLA leave begins; or
a "rolling" 12month period measured backward from the date an employee uses FMLA leave.